Re: [PATCH v2 5/7] usb: dwc3: add xhci-reset-on-resume property for power-loss resume

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Thu, Sep 03, 2026, Faisal Hassan wrote:
> On platforms where the USB controller loses power during system
> suspend, like SA8255P, resume triggers a Host Controller Error
> requiring full reinitialization.
> 
> The xhci driver supports XHCI_RESET_ON_RESUME to handle this,
> but dwc3 previously lacked platform-specific quirk configuration.
> Add a device property "xhci-reset-on-resume" that enables this
> quirk for controllers needing complete reinitialization after
> power loss during suspend.
> 
> Let dwc3 manage the quirk for the usb controller using
> software properties.
> 
> Co-developed-by: Sriram Dash <sriram.dash@oss.qualcomm.com>
> Signed-off-by: Sriram Dash <sriram.dash@oss.qualcomm.com>
> Signed-off-by: Faisal Hassan <faisal.hassan@oss.qualcomm.com>
> ---
>  drivers/usb/dwc3/core.c | 4 ++++
>  drivers/usb/dwc3/core.h | 5 +++++
>  drivers/usb/dwc3/host.c | 5 ++++-
>  3 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index fd5c2cd36c59..eb6ffd5148a7 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1712,6 +1712,10 @@ static void dwc3_get_software_properties(struct dwc3 *dwc,
>  					       &gsbuscfg0_reqinfo);
>  		if (!ret)
>  			dwc->gsbuscfg0_reqinfo = gsbuscfg0_reqinfo;
> +
> +		if (!dwc->xhci_reset_on_resume &&
> +		    device_property_read_bool(tmpdev, "xhci-reset-on-resume"))
> +			dwc->xhci_reset_on_resume = true;
>  	}
>  }
>  
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 608daeb7ef10..0ff23eb217bc 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1172,6 +1172,10 @@ struct dwc3_glue_ops {
>   * @suspended: set to track suspend event due to U3/L2.
>   * @susphy_state: state of DWC3_GUSB2PHYCFG_SUSPHY + DWC3_GUSB3PIPECTL_SUSPHY
>   *		  before PM suspend.
> + * @xhci_reset_on_resume: Enable XHCI_RESET_ON_RESUME quirk for the xHCI
> + *			  host controller. Set to true for platforms where
> + *			  the USB controller loses power during system suspend,
> + *			  requiring complete reinitialization on resume.
>   * @imod_interval: set the interrupt moderation interval in 250ns
>   *			increments or 0 to disable.
>   * @max_cfg_eps: current max number of IN eps used across all USB configs.
> @@ -1420,6 +1424,7 @@ struct dwc3 {
>  	unsigned		wakeup_configured:1;
>  	unsigned		suspended:1;
>  	unsigned		susphy_state:1;
> +	unsigned		xhci_reset_on_resume:1;

Can you move this after dis_split_quirk and add a blank line to separate
properties from dwc3 state/config fields?

>  
>  	u16			imod_interval;
>  
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index 96b588bd08cd..2170fcafc889 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -129,7 +129,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
>  
>  int dwc3_host_init(struct dwc3 *dwc)
>  {
> -	struct property_entry	props[6];
> +	struct property_entry	props[7];

This should be 8. There's already a fix patch for this. Hopefully it
gets picked up soon.

>  	struct platform_device	*xhci;
>  	int			ret, irq;
>  	int			prop_idx = 0;
> @@ -173,6 +173,9 @@ int dwc3_host_init(struct dwc3 *dwc)
>  	if (dwc->usb2_lpm_disable)
>  		props[prop_idx++] = PROPERTY_ENTRY_BOOL("usb2-lpm-disable");
>  
> +	if (dwc->xhci_reset_on_resume)
> +		props[prop_idx++] = PROPERTY_ENTRY_BOOL("xhci-reset-on-resume-quirk");
> +
>  	/**
>  	 * WORKAROUND: dwc3 revisions <=3.00a have a limitation
>  	 * where Port Disable command doesn't work.
> -- 
> 2.34.1
> 

Thanks,
Thinh